In a patient with metastatic hormone‑sensitive prostate cancer on abiraterone plus prednisone and androgen deprivation therapy, should I obtain a dual‑energy X‑ray absorptiometry (DXA) scan now and order somatic next‑generation sequencing (tissue or liquid biopsy) together with germline hereditary‑cancer testing?

Genomic Testing and Bone Health Management in Metastatic Hormone-Sensitive Prostate Cancer

Yes, you should order both germline and somatic NGS testing now (tissue or liquid biopsy), and obtain a baseline DXA scan to assess bone health given the patient is on abiraterone plus prednisone and ADT. 1

Genomic Testing: Both Germline and Somatic NGS Are Indicated

All patients with metastatic prostate cancer should undergo both germline and somatic DNA sequencing using panel-based assays. 1 This is a strong ASCO recommendation based on high-quality evidence from 2025.

Why Both Tests Matter:

• Somatic testing identifies actionable mutations (particularly BRCA1/2 and other homologous recombination deficiency genes) that predict response to PARP inhibitors, which have demonstrated survival benefit in metastatic castration-resistant prostate cancer 1
• Germline testing has critical implications for cascade testing in family members and screening for additional cancers in the patient, independent of treatment decisions 1
• Even when germline testing is positive for actionable mutations (e.g., BRCA2), somatic testing remains useful to confirm loss of heterozygosity and identify additional actionable alterations 1

Tissue vs. Liquid Biopsy Decision:

• Archival tissue samples are preferred for initial testing 1
• Liquid biopsy (ctDNA) is preferred when:
  • No accessible metastatic site exists for biopsy 1
  • Sequential/repeat testing is needed 1
• Metastatic biopsy is preferred in settings of minimal disease burden with low ctDNA fraction 1

For your patient currently on treatment with likely adequate disease burden, either archival tissue (if available) or liquid biopsy would be appropriate initial choices. 1

DXA Scan: Mandatory for Bone Health Assessment

Yes, obtain a baseline DXA scan now. Your patient is on multiple bone-damaging therapies (ADT, abiraterone, and prednisone), creating substantial fracture risk.

Why DXA Is Critical:

• Men on ADT experience accelerated bone loss at rates up to 4.6% annually in the hip, femoral neck, and lumbar spine 2
• Fracture risk increases 2-fold to 5-fold compared to men not on ADT 2
• The combination of ADT plus prednisone (from the abiraterone regimen) compounds bone loss risk 1

Bone Protection Algorithm Based on DXA Results:

If T-score ≤ -2.0 OR presence of 2 risk factors for fracture:

• Initiate bone-targeted therapy immediately 1
• Denosumab 60 mg subcutaneously every 6 months is the preferred first-line agent for men on ADT 1, 2
• Alternative: Oral bisphosphonates (alendronate 70 mg weekly or risedronate) or IV zoledronic acid 4-5 mg every 6-12 months 1, 2

Risk factors to assess include: 1

• Age >65 years
• BMI <24
• Current or history of smoking
• Personal history of fragility fracture after age 50
• Family history of hip fracture
• Oral glucocorticoid use >6 months (your patient is on prednisone)

Mandatory Supplementation Regardless of DXA Results:

All patients on ADT require: 1, 2

• Calcium 1000-1200 mg daily
• Vitamin D 800-1000 IU daily

Monitoring Strategy:

• Repeat DXA scanning annually while on ADT 2
• If annual BMD decrease exceeds 10% (or 4-5% if osteopenic at baseline), evaluate for secondary causes of bone loss and initiate antiresorptive therapy 1

Critical Pitfalls to Avoid

For Genomic Testing:

• Do not wait for disease progression to order testing – testing should occur now while the patient is hormone-sensitive, as results guide future treatment decisions when castration resistance develops 1
• Do not order only one type of test (germline OR somatic) – both are required as they provide complementary information 1
• Do not use prognostic-only biomarkers to guide treatment outside clinical trials – only predictive biomarkers (like BRCA1/2 for PARP inhibitors) should direct therapy 1

For Bone Health:

• Do not delay DXA scanning – baseline assessment is essential before significant bone loss occurs 1, 2
• Do not start bone-targeted therapy without dental evaluation – this dramatically increases osteonecrosis of the jaw (ONJ) risk, particularly with denosumab or bisphosphonates 3
• Do not forget calcium/vitamin D supplementation – inadequate supplementation can lead to severe hypocalcemia, especially with denosumab 2, 3
• Do not assume prednisone 5 mg daily is "low-risk" – chronic glucocorticoid use at any dose contributes to bone loss and is a recognized risk factor 1

Practical Implementation

Order now:

1. Germline genetic testing panel (includes BRCA1/2, ATM, PALB2, CHEK2, and other cancer predisposition genes) 1
2. Somatic NGS panel (tissue if archival sample available, or liquid biopsy/ctDNA) 1
3. DXA scan of lumbar spine and hip 1, 2
4. Serum calcium, 25-hydroxyvitamin D, and creatinine clearance 2
5. Calculate FRAX score (enter ADT as secondary osteoporosis) 2

Initiate immediately:

• Calcium 1000-1200 mg daily 1, 2
• Vitamin D 800-1000 IU daily 1, 2

After DXA results:

• If T-score ≤-2.0 or ≥2 risk factors present: arrange dental evaluation, then initiate denosumab 60 mg SC every 6 months 1, 2